DM74ALS640AWMX

Overview

The DM74ALS640AWMX is an inverting octal bus transceiver manufactured by onsemi, utilizing the Advanced Oxide-isolated Ion-implanted Schottky TTL process. It supports asynchronous two-way communication between data buses with a supply voltage range of 4.5 V to 5.5 V. The device features 3-state outputs and operates within a temperature range of 0°C to +70°C. Propagation delay is guaranteed at 11 ns maximum for both LOW-to-HIGH and HIGH-to-LOW transitions under specified load conditions.

Feature Summary

• Advanced Oxide-isolated Ion-implanted Schottky TTL process
• Switching performance guaranteed over full temperature and VCC supply range
• PNP input design reduces input loading

Applications

• Asynchronous bidirectional data buses
• Memory systems
• Microprocessor systems

Procurement Notes

Verify that the ordering code includes the 'X' suffix to confirm tape and reel packaging. Confirm the manufacturer origin, as this component was originally produced by Fairchild Semiconductor before acquisition. Ensure the SOIC-20 package matches the required footprint for the target PCB layout.

Selection Notes

Select this component when an inverting octal bus transceiver is required for ALS logic families. Verify that the 3-state output capability meets system isolation requirements. Check that the 11 ns propagation delay fits the timing constraints of the specific bus architecture being implemented.

Part Context

This part belongs to the 74ALS series of logic integrated circuits. It functions as a single circuit containing eight channels of bus transceivers. The device is designed to interface between different bus structures while providing electrical isolation through its enable input control.

Replacement Considerations

DM74ALS640AWM (Tube Packaging)

FAQ

What is the function of the DIR input?

The direction control (DIR) input determines the data transmission path, allowing data to flow from the A bus to the B bus or vice versa.

How does the G input affect operation?

The enable input (G) can be used to disable the device, effectively isolating the buses when set to a high logic level.